The present invention relates to a means of driving the rear treads on an all season vehicle and particularly in accordance with a direction imparted to the front steering mechanism.
The present invention makes use of a hydraulic control system for imparting a different speed relationship to each tread while maintaining a correct steering direction for the vehicle. The mechanism responds to the hydraulic system in both forward and rearward movement and also reacts properly in a neutral position. While in a normal driving position, the steering mechanism of the vehicle will turn the front steering elements in the proper direction and produce a proper driving relationship to the rear treads to track that front steering mechanism. When it is desirable to overcome the control position imparted to the two rear treads, a deadman switch may be depressed which permits a rotational movement of the deadman stick causing the valves directing the hydraulic flow to be oriented to give an exaggerated flow position.